The audio component of a television signal can have significant commercial value even when not accompanied by the corresponding video. This is particularly true in connection with news, sports and traffic broadcasts, which often contain a significant amount of audio information beyond the corresponding video information that accompanies the transmission. To this end, various apparatus have been developed to provide television audio, without the video, in a number of different environments. One such environment is the mobile vehicle, such as a truck, car, recreational vehicle, etc.
One apparatus purportedly suitable for receiving television audio in an automobile is set forth in U.S. Pat. No. 4,905,303, issued Feb. 27, 1990, to Johnson et al. The '303 patent discloses a converter that converts audio signals associated with commercial television transmissions for input into conventional AM/FM automobile receivers to facilitate listening to the audio portions of telecasts on conventional radios. Channel selection is provided by the user through a combined switch/potentiometer circuit that is used to generate the requisite tuning voltages. More particularly, the user switches between VHF low, VHF high and UHF frequency bands using a switch. Tuning of a particular television channel within the selected frequency band is accomplished by manual manipulation of a potentiometer by the user. The user is not provided with any indication of the channel to which the apparatus is tuned. Rather, the positions of the switch and potentiometer must be memorized by the user if the user is to return to a given television channel. Further, tuning a television channel with this configuration can be awkward and may be hazardous when used in a moving vehicle given that such complicated tuning steps are distracting to the driver.
Another vehicle-based receiver that is constructed to receive selected television audio broadcasts is illustrated in U.S. Pat. No. 5,276,909, to Milner et al. The receiver disclosed in the '909 patent is disposed between the vehicle's antenna and the vehicle's AM car radio. In furtherance of the stated goal of the disclosed apparatus, the receiver is specifically adapted to receive traffic information broadcasts that are transmitted on the second audio program (SAP) of television broadcast channels. More particularly, the receiver is adapted to selectively monitor predetermined broadcast segments of a specially formatted broadcast signal of the SAP. However, the receiver further includes a “TV Sound” mode of operation. In that mode, a one or two digit channel number is entered through a keyboard having keys 0-9, followed by activation of a “TV Sound” command key. Alternatively, a preset channel may be selected by pressing a selected command key. The '909 patent fails to disclose any details as to how the preset channel function is implemented.
The present inventors have recognized and addressed numerous problems associated with such prior television audio receivers. For example, a driver or passenger operating one of the foregoing television audio receivers in a vehicle is not provided with any indication as to which television broadcast channel the receiver is tuned. Additionally, selection of the television broadcast channel that a user wishes to listen to can still be quite complex. Further, the user must know which of the many television broadcast channels are used in a particular region in order to operate one of the foregoing receivers. These receivers, therefore, are not readily adaptable to operation in different broadcast regions—a significant detriment to a vehicle operator that frequently travels between multiple broadcast regions. Still further, none of the foregoing references set forth a physical construction for the receiver that can be readily installed in a vehicle. Accordingly, the present inventors have developed a television audio receiver that is particularly suitable for operation in a vehicle and that includes various design aspects that deal with one or more of the foregoing problems that they have recognized.